Woodwind instrument and airflow adjuster

ABSTRACT

A woodwind instrument such as a clarinet includes a main tube including an upper tube and a lower tube and a correcting tone hole used solely for interval correction is formed in the lower tube. An airflow adjuster is installed in the correcting tone hole. The airflow adjuster is formed in an M shape by bending a film member at three positions. The airflow adjuster can properly arrange a turbulent airflow in the correction tone hole during performance and can reduce undesired sound generated from the correcting tone hole.

INCORPORATED BY REFERENCE

Priority is claimed on Japanese Patent Application No. 2011-101048,filed Apr. 28, 2011, the content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a woodwind instrument and an airflowadjuster, and more particularly, to a woodwind instrument and an airflowadjuster which can reduce undesired sound generated from a tone hole.

2. Description of Related Art

Woodwind instruments such as a clarinet described in Japanese UnexaminedPatent Application, First Publication No. H01-158491 have been widelyused. In a clarinet, a bell is coupled to a lower tube of a main tubeformed from an upper tube and a lower tube. Tone holes are formed in themain tube at predetermined intervals along the axis line directionthereof. By closing and opening these tone holes, the effective lengthof the tube is changed to perform specific tones. Each tone hole isopened and closed through the use of a key with a pad or the like bymanipulating the key with a finger tip. Here, a clarinet having aninterval-correcting tone hole formed in a bell part thereof so as tocorrect the interval of a low-pitched tone (LowE) is known.

However, in the clarinet in which the interval is corrected as describedabove, since a tone hole is formed in the bell part independently of thetone holes formed in the main tube, there is a problem in that thenumber of components increases and the adjustment of the keys located inthe lower tube and the bell part is complicated. Since the number ofcomponents increases, there is a problem in that the work load foradjusting the clearances between the components increases and themanufacturing cost thereof also increases. In addition, when a usercombines the bell part with the lower tube, there is a problem in thatthe keys located therein may collide and bend or the like and thus thekeys may be damaged. Therefore, it can be thought that in order to solvethe above-mentioned problems, the interval-correcting tone hole could beformed in the lower tube. In this case, there is a problem in that inorder to achieve the equivalent interval correction effect, the tonehole should be formed with a hole diameter smaller than that of the tonehole formed in the bell part and this creates undesired sound as windnoise (sound such as hissing noise) from the tone hole duringperformance. Here, Related Arts 1 to 3 described below can be consideredas techniques for suppressing the generation of undesired sound whileforming an interval-correcting tone hole in the lower tube.

[Related Art 1]

The hole diameter of the interval-correcting tone hole is set to begreater than the hole diameter of the other tone holes used for themusical performance.

[Related Art 2]

The gap between the interval-correcting tone hole and the key with a padat an open position at which the tone hole is opened and closed, thatis, the pad opening at the interval-correcting tone hole, is set to beas large as possible.

[Related Art 3]

The axis line direction of the interval-correcting tone hole is obliqueabout the diameter direction of the lower tube and air flowing out ofthe tone hole is made not to come in contact with the open key with apad.

However, in Related Art 1, when the hole diameter of theinterval-correcting tone hole is increased so as to further reduceundesired sound, the distance of an arm connecting the pad plate to akey tube decreases by the amount by which a pad plate is enlarged.Accordingly, there is a problem in that the stroke of a key with a padis insufficient, thereby making the performance difficult. Here, it ispossible to enlarge the pad opening to satisfactorily guarantee thestroke. However, in this case, the fingering distance increases, and ifan effort to reduce the fingering distance by changing the leverageratio is made, performance is made more difficult by a spring beingheavier or the like. In Related Art 2, since the pad opening isenlarged, performance is also difficult as described above.

In Related Art 3, since the tone holes other than theinterval-correcting tone hole are formed by drilling the main tube inthe diameter direction thereof, it is necessary to separately prepare amachine solely for machining the interval-correcting tone hole. That is,a machining shaft for the interval-correcting tone hole should be added,whereby a facility load of a high-function machine tool correspondingthereto increases.

SUMMARY OF THE INVENTION

An object of the invention is to provide a woodwind instrument and anairflow adjuster in which the hole diameter of a tone hole can be set tobe smaller and the generation of undesired sound can be reduced.

Another object of the invention is to provide a woodwind instrument andan airflow adjuster in which the number of components or themanufacturing cost thereof can be reduced and the performance thereofcan be prevented from becoming difficult.

To achieve the above-mentioned objects, according to an aspect of theinvention, there is provided a woodwind instrument including an airflowadjuster that is installed in a tone hole formed in a tube.

In the woodwind instrument, the tube may include an upper tube and alower tube and the tone hole having the airflow adjuster installedtherein may be formed in the lower tube.

In the woodwind instrument, the tone hole having the airflow adjusterinstalled therein may be a tone hole used only for interval correction.

In the woodwind instrument, the airflow adjuster may be formed bybending a film member at plural positions.

In the woodwind instrument, a stepped portion may be formed in the innercircumferential surface of the tone hole and the airflow adjuster may bemade to engage with the stepped surface.

According to another aspect of the invention, there is provided anairflow adjuster that is installed to be inserted into a tone holeformed in a tube of a woodwind instrument.

According to the invention, since the airflow adjuster is installed inthe tone hole, it is possible to properly arrange a turbulent airflow inthe tone hole during the performance as described later and to reduceundesired sound generated from the tone hole while reducing the holediameter. Accordingly, when the woodwind instrument is a clarinet, it ispossible to form an interval-correcting tone hole in the lower tube, toreduce the number of components, to reduce the working load such as theadjustment work of keys, and to suppress an increase in manufacturingcost. Since the hole diameter of the tone hole having the airflowadjuster installed therein can be reduced, it is possible to avoid theinsufficient stroke of a key with a pad described in the related art orthe increase in fingering distance and thus to prevent the performancefrom becoming difficult. It is possible to form the interval-correctingtone hole and the other tone holes using machining methods and machiningfacilities of the related art and thus to suppress an increase infacility load.

When the airflow adjuster is formed by bending a film member at aplurality of positions, it is possible to make the structure very simpleand to easily suppress the generation of undesired sound. In addition,using the elasticity of the airflow adjuster, the airflow adjuster isdeformable to be able to stretch and contract in the diameter directionof the tone hole and can be easily attached to the tone hole for a shorttime by pressing the airflow adjuster to the inner circumferentialsurface of the tone hole so as to be supported therein.

When the stepped portion is formed on the inner circumferential surfaceof the tone hole and the airflow adjuster is made to engage with thestepped portion, it is possible to regulate the displacement of theairflow adjuster in the tone hole and thus to prevent the airflowadjuster from accidentally falling out of the tone hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view illustrating a woodwind instrument according toan embodiment of the invention.

FIG. 1B is a partial rear view illustrating the woodwind instrumentshown in FIG. 1A.

FIG. 2A is a sectional view taken along line A-A of the woodwindinstrument shown in FIG. 1B.

FIG. 2B is a rear view of a tone hole of the woodwind instrument shownin FIG. 2A when seen in the direction of B.

FIG. 2C is a perspective view illustrating an airflow adjuster accordingto an embodiment of the invention.

FIGS. 3A, 3B, and 3C are graphs illustrating a periodic variation of asecond partial tone during performance of a lowest-pitched tone in thewoodwind instruments according to the related art and the embodiment ofthe invention.

FIG. 4 is a sectional view illustrating a woodwind instrument accordingto another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, exemplary embodiments of the invention will be describedwith reference to the accompanying drawings.

In the following description, as long as not otherwise specified, theterms, “up” and “down”, mean upward and downward in paper surface ofFIG. 1A. That is, a mouthpiece of a woodwind instrument is located at anupper position and a bell part is located at a lower position.

Referring to FIGS. 1A and 1B, a woodwind instrument 10 is a Boehm B-flatclarinet in this embodiment. The woodwind instrument 10 includes a maintube 13 which is a tube having keys 11 arranged on the outercircumferential surface thereof and a bell part 14 which is connected toa lower tube of the main tube 13. The main tube 13 includes an uppertube 17 and a lower tube 18 coupled to each other. A plurality of toneholes 20, 21, and 24 are formed in the upper tube 17 and the lower tube18. Keys 11 and 26 are disposed in a plurality of tone holes so as toopen and close the tone holes. Among these tone holes, two tone holes 20and 21 are tone holes (hereinafter, referred to as “correcting toneholes 20 and 21”) disposed solely for interval correction. The othertone holes 24 are tone holes which are opened and closed to switch theinterval of the clarinet. In this embodiment, no tone hole is formed inthe bell part 14.

The lower correcting tone hole 20 is opened to correct the interval of alowest-pitched tone (Low E) which is generated by closing all the toneholes 24. The upper correcting tone hole 21 is opened at the same timeas opening the lower correcting tone hole 20, thereby correcting theinterval of the tone (Low F) higher a half step than Low E. By openingthe correcting tone holes 20 and 21, the corrected interval can beincreased by 10 to 20 cents.

The correcting tone holes 20 and 21 are opened and closed by keys with apad 26, as shown in FIG. 2A. These keys with a pad 26 are connected toan arm 27. When performing the lowest-pitched tone (LowE), a playerpresses a Low E/F tone correcting key 30 at the same time as pressing aLowE/B key 31 (see FIG. 1A). Accordingly, the arm 27 rotates to make thekey with a pad 26 come apart from the outer circumferential surface ofthe lower tube 18, whereby the correcting tone hole 20 is opened. Whenperforming the tone (Low F) higher a half step than the lowest-pitchedtone, the player presses the Low E/F interval correcting key 30 at thesame time as pressing a Low F/C key 32 (see FIG. 1A), thereby openingthe correcting tone holes 20 and 21. In each of the correcting toneholes 20 and 21, the axis line direction of the corresponding tone holeis parallel to the diameter direction of the lower tube 18.

As shown in FIG. 2A, an airflow adjuster 33 is installed in the lowercorrecting tone hole 20.

As shown in FIGS. 2B and 2C, the airflow adjuster 33 is formed in an Mshape by bending a band-like film member formed of a resin material suchas polyester at plural positions. The airflow adjuster 33 is installedat the position and with the size shown in FIG. 2A. Specifically, theairflow adjuster 33 is located in a middle part in the axis linedirection of the tone hole 20 so as not to protrude from both openingends of the correcting tone hole 20. The airflow adjuster 33 is attachedto the tone hole 20 so that plural planes formed by the bending areparallel to the axis line of the tone hole 20. The length (the thicknessof the lower tube 18) L of the tone hole 20 is 6.2 mm and the length lof the airflow adjuster 33 is 2.8 mm. The airflow adjuster 33 isdisposed so as to be invisible when seen from the end section side ofthe tone hole 20 (the direction of arrow C in FIG. 2A).

Since the airflow adjuster 33 is formed in a zigzagged M shape, it isdeformable so as to be able to expand and contract in size in the widthH direction in FIG. 2C. Accordingly, the airflow adjuster 33 can be madeinto a folded state by picking up the airflow adjuster 33 from the widthH direction by the use of a pair of forceps or the like and can beinserted into the correcting tone hole 20 in this state. When thepinching of the airflow adjuster 33 by the pair of forceps is released,the airflow adjuster 33 returns easily to the original shape due to theelastic force of the material and thus the magnitude of the width Hincreases. Accordingly, both ends of the airflow adjuster 33 can bestrongly pressed against the inner circumferential surface of thecorrecting tone hole 20 and the position of the airflow adjuster 33 inthe correcting tone hole 20 is thus determined. The diameter φT of thetone hole 20 is 3.5 mm. Accordingly, when the airflow adjuster 33 isattached to the tone hole 20 (the state shown in FIG. 2B), the width His slightly smaller than 3.5 mm.

In the woodwind instrument 10 according to this embodiment, the resultsof measurement and comparison of a periodic variation of a secondpartial tone (double overtone) when performing the lowest-pitched tone(musical notation E, actual sound D) are shown in FIGS. 3A to 3C. FIGS.3A and 3B show the periodic variation in a comparative example. Thegraph of FIG. 3A shows the periodic variation measured when thecorrecting tone hole 20 is closed by the key with a pad 26 and the graphof FIG. 3B shows the periodic variation measured when the correctingtone hole 20 is opened without installing the airflow adjuster 33 in thecorrecting tone hole 20. FIG. 3C shows the periodic variation in thisembodiment. The graph of FIG. 3C shows periodic variation measured whenthe correcting tone hole 20 is opened with the airflow adjuster 33installed in the correcting tone hole 20.

In the graph of FIG. 3A (where the tone hole 20 is closed), the averagefrequency is several Hz lower than a desired interval (a frequency of293.7 Hz), but the variation in frequency is small and the amount ofundesired sound is small. In the graph of FIG. 3B (where the tone hole20 is opened and the airflow adjuster 33 is not installed), the averagefrequency is close to the desired interval (a frequency of 293.7 Hz),but the variation in frequency is great and distorted noise isrecognized from the performed tone. In the graph of FIG. 3C (where thetone hole 20 is opened and the airflow adjuster 33 is installed), theaverage frequency is the desired interval (a frequency of 293.7 Hz), theinterval is musically correct, the variation in frequency is small, andthere is little undesired sound. Therefore, according this embodiment,it is possible to excellently correct the interval of the lowest-pitchedtone and to suppress the generation of undesired sound, compared withthe comparative examples.

In addition, significant variations in frequency like those in the graphare not acceptable in the fundamental tone and the third to tenthpartial tones during performance. The clarinet is basically configuredto generate only odd overtones, but the second partial tone actually hasa sound pressure level of about −30 dB with respect to the fundamentaltone component, which is sufficiently perceivable. It is understood thatthe reason is that the second partial tone is generated due to the airdisturbance caused secondarily in a half period in which air particlesmove from the inside of the instrument to the outside via the tone holein a period of air-column resonant vibration and a half period in whichair particles move from the outside of the tone hole to the inside ofthe instrument. Therefore, the perception of the second partial tone isdifferent in principle from a wind noise generating mechanism due to thedisturbance of a fast continuous fluidized airflow.

Measurement using PIV (Particle Image Velocimetry) in the woodwindinstrument 10 will be described below.

PIV-specific lubricant particles (DOS) of about 1 micron are transportedinto the main tube 13 along with air from the mouthpiece, a laser beamis set to be vertical or horizontal in a simple box covered with ablackout curtain, the velocity of particles in the main body 13 or inthe vicinity of the tone holes 20 and 24 during the resonance of alowest-pitched tone in which the lowest-pitched tone is blown with anautomatic blowing device is measured. The flow rate in the vicinity ofthe correcting tone hole 20 and the flow rate in the vicinity of thetone hole 24 close to the location of the correcting tone hole 20 aremeasured and compared with each other. The flow rates when the airflowadjuster 33 is inserted into the correcting tone hole 20 and when theairflow adjuster 33 is not inserted are measured and compared with eachother. As a result, it can be seen that the flow of air in the vicinityof the tone hole 24 is different from the flow of air in the vicinity ofthe correcting tone hole 20. In the tone hole 24, since the diameter isgreater than that of the correcting tone hole 20, it can be seen thatthe flow rate from the outside to the inside of the lower tube 18 andthe flow rate from the inside to the outside of the lower tube 18 areboth small, and there is no great difference between the flows of air onthe right and left sides of FIGS. 1A and 1B with respect to the verticaldirection. On the contrary, regarding the flow of air in the vicinity ofthe correcting tone hole 20, it is thought that the flow rate from theoutside to the inside of the lower tube 18 and the flow rate from theinside to the outside of the lower tube 18 are relatively great and thisserves as a factor for generating undesired sound. In addition, in thecorrecting tone hole 20, the flow of air suctioned from the outside tothe inside of the lower tube 18 is set to the vertical direction and theflow of air erupted from the inside to the outside of the lower tube 18is set to the horizontal direction, but the flow rates of both theeruption of an airflow to the outside and the suction of an airflow tothe inside are suppressed by installing the airflow adjuster 33 in thecorrecting tone hole 20. Particularly, at the time of eruption from theinside to the outside of the lower tube 18, it can be seen that the flowof air around the correcting tone hole 20 is uniform across the entireperiphery. Therefore, regarding the flow of air around the correctingtone hole 20, it is thought that a difference in the flow of air betweenthe vertical direction and the horizontal direction does not occur whenthe airflow adjuster 33 which limits the boundary conditions of anairflow pressure distribution inserted therein, and thus undesired soundis reduced.

The range of hole diameters with which the correcting tone holes 20 and21 can be used as interval-correcting tone holes, the airflow adjuster33 is inserted into the tone holes, and the effect of a reduction inundesired sound expected can be set to the range of 0.1≦φT/φM≦0.5, whereφM represents the inner diameter of the lower tube 18, φT represents thehole diameter of the correcting tone holes 20 and 21, andφT/φM=3.5/18.77=0.19 is set in this embodiment. The effective range ofthe vertical position of the correcting tone hole 20 is when the centerposition is within 23.0 mm above from the boundary position (from thelower end surface of the lower tube 18) between the lower tube 18 andthe bell part 14. The ratio (l/L) of the length l of the airflowadjuster 33 to the length (the thickness of the lower tube 18) L of thetone hole 20 in this embodiment is l/L=2.8/6.2=0.45. The length l of theairflow adjuster 33 is preferably selected so that the ratio l/L isequal to or less than 0.9. The ratio (l/φT) of the length l of theairflow adjuster 33 to the diameter φT of the tone hole 20 isl/φT=2.8/3.5=0.80. This ratio l/φT is preferably selected to be equal toor more than 0.2. That is, the length l of the airflow adjuster 33 is inthe range of 0.2φT≦l≦0.9L.

According to this embodiment, the hole diameter of the correcting tonehole 20 formed in the lower tube 18 can be set to be smaller than thehole diameter of the tone holes 24 and thus the reduction of undesiredsound generated from the correcting tone hole 20 can be achieved.Accordingly, it is possible to reduce the number of components and toreduce the load such as the adjustment of keys to achieve a decrease incost, compared with the related art in which the correcting tone hole isformed in the bell part 14. In addition, since the hole diameter of thecorrecting tone hole 20 decreases, it is possible to avoid aninsufficient stroke of the key with a pad 26 or an increase in fingeringdistance and to prevent the performance from becoming difficult.

As described above, the structure and method for putting the inventioninto practice are mentioned above, but the invention is not limited tothe constitution and method.

The shape of the correcting tone hole 20 can be modified in variousmanners and, for example, the constitution shown in FIG. 4 may beemployed. In FIG. 4, the correcting tone hole 20 includes alarge-diameter portion 36 formed by partially increasing the diameter ofan intermediate portion in the axis line direction in the innercircumferential surface thereof and the airflow adjuster 33 can beattached to the large-diameter portion 36. Accordingly, the airflowadjuster 33 can engage with the step-formed surface of thelarge-diameter portion 36, thereby preventing the airflow adjuster 33from accidentally falling out of the correcting tone hole 20.

An adhesive may be applied to the airflow adjuster 33 in advance andthen the airflow adjuster 33 may be inserted into the correcting tonehole 20. Accordingly, the airflow adjuster 33 is strongly fixed into thetone hole 20, thereby preventing the airflow adjuster 33 from rotatingin the circumferential direction of the correcting tone hole 20.

The airflow adjuster 33 is not limited to the above-mentioned M shape,but may be formed in shapes such as V, N, and W by bending the filmmember at one or more positions, or may be formed to have a regionconnected to the shapes and parallel to the inner circumferentialsurface of the correcting tone hole 20. A plurality of sheet members maybe combined to form the airflow adjuster having a cross shape or alattice shape. The airflow adjuster may also be a spiral shape. Theorientation of the circumferential direction of the correcting tone hole20 in which the airflow adjuster 33 is located is not limited to thetrend shown in the drawing, but may be appropriately changed.

The airflow adjuster 33 may be formed of paper or a thin metal plate.The airflow adjuster 33 is not limited to the band-like shape and aporous member (such as a foamed resin or a pumiceous member) may beinserted into the correcting tone hole 20.

The airflow adjuster according to the invention may be applied toclarinets other than the Boehm B-flat clarinet or to other woodwindinstruments.

While the invention has been drawn and described with reference to aspecific embodiment, the above-mentioned embodiment may be modified invarious forms in shape, position, or arrangement by those skilled in theart without departing from the technical concept and object of theinvention.

Therefore, the above description defining the shape or the like isintended to facilitate the understanding of the invention, but is notintended to limit the invention. Accordingly, the invention is definedonly by the appended claims and includes members departing from a partor all of the definitions of the shapes or the like.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplaryembodiments of the invention and are not to be considered as limiting.Additions, omissions, substitutions, and other modifications can be madewithout departing from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

What is claimed is:
 1. A woodwind instrument comprising: a tube having aplurality of tone holes; and an airflow adjuster statically disposed ina selected tone hole of the plurality of the tone holes, wherein theairflow adjuster is a film member bent at a plurality of positions. 2.An airflow adjuster comprising a bent film member configured to beinserted into a tone hole in a tube of a woodwind instrument, whereinthe bent film member comprises a plurality of planes.
 3. The airflowadjuster according to claim 2, wherein each of the plurality of planesis parallel to an axis line of the tone hole.
 4. The airflow adjusteraccording to claim 2, wherein the airflow adjuster has a height lessthan a corresponding height of the tone hole.
 5. An airflow adjustercomprising a bent film member configured to be inserted into a tone holein a tube of a woodwind instrument, wherein the bent film member isdeformable.
 6. A woodwind instrument comprising: a tube having aplurality of tone holes; and an airflow adjuster disposed in a selectedtone hole of the plurality of tone holes, wherein the airflow adjusteris a film member bent at a plurality of positions.
 7. The woodwindinstrument according to claim 6, wherein the film member comprises aplurality of planes.
 8. The woodwind instrument according to claim 7,wherein each of the plurality of planes is parallel to an axis line ofthe selected tone hole.
 9. The woodwind instrument according to claim 6,wherein the airflow adjuster has a height less than a correspondingheight of the selected tone hole.
 10. The woodwind instrument accordingto claim 6, wherein the bent film member is deformable.
 11. A woodwindinstrument comprising: a tube having a plurality of tone holes; and anairflow adjuster disposed in a selected tone hole of the plurality oftone holes, wherein the selected tone hole comprises a stepped innersurface and the airflow adjuster is configured to engage with thestepped inner surface, wherein the airflow adjuster is a bent filmmember comprising a plurality of planes.
 12. The woodwind instrumentaccording to claim 11, wherein each of the plurality of planes isparallel to an axis line of the selected tone hole.
 13. The woodwindinstrument according to claim 11, wherein the bent film member isdeformable.
 14. A woodwind instrument comprising: a tube having aplurality of tone holes; and an airflow adjuster disposed in a selectedtone hole of the plurality of tone holes, wherein the selected tone holecomprises a stepped inner surface and the airflow adjuster is configuredto engage with the stepped inner surface, wherein the airflow adjusterhas a height less than a corresponding height of the selected tone hole.